On the 9th of june 2023, I found several black, round ascomata on a dead stem of Phragmites australis, partially sunk into the substrate. The Thyriothecia are not flat but somewhat like a flattened globe.
Substrate: Phragmites australis;
Thyriothecia: 222-235 x 220-234 µm; orbicular; covered with an irregular network of hyphae, at the margin short light brown or hyaline fringes;
Ostiole: diameter 18 µm;
Asci: clavate, Lugol and Melzer negative, 8-spored, 54-70 x 6-9 µm;
Paraphyses: 85 x 4 µm ; filiform, constricted at the different septa, cells of different width and up to 15 µm long
Spore: narrowly fusiform, with 1 to 4 septs, rounded at the poles and narrowing the base; 23-29 x 3.3-4 µm
Brown anchor hyphae: 70 x 5 µm.

The article "The Genera Trichothyrina and Actinopeltis in Britain" by J.P. Ellis mentions only one species with septated spores namely Trichothyrina norfolciana but with hyaline spores as substrate Carex riparial.
Any help is welcome as I have too little experience with this genus.

Many thanks, in advance,

François Bartholomeeusen